The sign was later removed when owner Beth Murphy was made aware of the outrage it had sparked on Twitter.

One user tweeted a picture of the sign with the note, "Not the way to remember a tragedy."

Murphy told the Chicago Tribune that the employee responsible for the sign will face disciplinary action.

"Some guys thought it would be clever," Murphy told the Tribune. "Obviously we are ashamed. I'm so upset. We put up (a sign with) our sincerest apologies. My father was a veteran, and my uncles. This was just not us. Personally this is devastating to me. I apologize to everyone who was offended."

The bar also apologized on Facebook and Twitter.

“We couldn’t be more embarrassed and ashamed by the actions of our staff this morning. The sign has been removed and we cannot start apologizing enough for the thoughtless disregard for decency,” the bar posted on its Facebook page.

Commenters advised the bar to fire the employee responsible and also make a contribution to the Wounded Warrior Project. Many said they weren’t offended.

“I saw the sign and thought it was somewhat humorous and made perfect sense being at a bar,” said one man. “People have lost their sense of humor, and are always looking to be offended.”

One commenter said this wasn’t the first time Murphy’s did something offensive.